Inductor-capacitor (L-C) resonant circuits (also known as tank circuits) are widely used in electronic systems, for example for clock signals, oscillators, switching power supplies, and wireless communications. One common measure used to characterize L-C resonant circuits is the Q-factor (also known as the quality factor). One definition of Q-factor for L-C circuits is the resonant frequency of an L-C resonant circuit divided by the half-power bandwidth of the L-C resonant circuit. In some systems, for maximum efficiency and sensitivity, the L-C resonant circuit must be calibrated to maximize the Q-factor at a predetermined frequency. In some calibration processes, a modulated test tone is injected into the L-C resonant circuit using external instrumentation, which is time consuming and complex. In some systems, components used for calibration cause additional loading of the L-C resonant circuit, which affects measurement accuracy and may provide unwanted coupling to noise sensitive circuits. There is a need for a simple, fast, and accurate calibration mechanism for L-C resonant circuits.